Murakumo opened a chasm in the floor... but for some reason, there is only a white line crossing the monster... i noticed that a lot in this manga, the attacks, even powerful ones, don't seem to have much of an outward effect (with a few exceptions), but they clearly are capable of destruction.
Now that I think... maybe it is an inbuilt mechanic of the abilities system so that they don't damage the monster too much, so they can use them... can be an artistic choice too, but it feels more "in story" intentional.
Wait, should we know who this one is?
Her name, no... but she clearly is from Elitia's old party, the one that forced a cursed sword on her, then abandoned her and her friend when they decided she was useless to them.
Translation... a bunch of crazy psycho assholes that only care about themselves.